Digital cellular land mobile telecommunication systems
Associated signalling channel
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- 2.5 Handover
- 2.5.2 Hard handover
- 2.6 Registration and mobility management
- 2.7 Security features
- 2.8 Mobile station identification
- 2.9 Services
- 1 Introduction
- 2 Technical overview
2.4 Associated signalling channelSignalling between the mobile and base stations, after the transition to the traffic channel, is accomplished by “blank and burst” or “dim-and-burst” in the traffic channel. Blank-and-burst pre-empts one or more traffic frames and substitutes the signalling message. Dim-and-burst is similar, except the speech coder is informed that it may not use full rate. A full-rate frame thus consists of the half-rate or lower rate speech data and a half frame of signalling data. The dim and-burst method has less impact on voice quality. In both cases the receiving speech codec is notified that the frame was pre empted, and it can take mitigating actions, possibly different than those it would take when the frame is in error. 2.5 Handover2.5.1 Soft handoverThe system supports seamless soft handover. This is accomplished by two or more base stations radiating the output traffic for the mobile station. The mobile station combines the signal from these base stations. This provides spatial diversity, thus improving quality and coverage; furthermore, soft handovers are undetectable by the users. 2.5.2 Hard handoverHard handover is supported for instances when the mobile station is transferred between disjoint active sets, different CDMA frequency assignments, or different frame offsets. Hard handovers are also supported to transfer a mobile station from CDMA PCS to CDMA cellular and analogue cellular. 2.6 Registration and mobility managementMobility management is supported by nine operator-selectable registration mechanisms. The nine types of registration are: – Power up : the mobile station registers when it is turned on. – Power down : the mobile station registers when it is turned off. – Time based : the mobile station registers when a timer expires. – Distance based : the mobile station registers when the distance between the current base station and the last base station in which it last registered exceeds a threshold. – Zone based : the mobile station registers when it enters a new zone. – Parameter change : the mobile station registers when certain of its stored parameters change. – Ordered : the mobile station registers when requested by the base station. – Traffic channel : the base station can interrogate a mobile station that has been assigned to a traffic channel, thereby accomplishing a registration. – Implicit : any origination or page response constitutes an implied registration. 2.7 Security featuresBoth global and unique challenge-response authentication procedures are available to prevent various types of over the air service fraud. All traffic channel transmissions can be protected by the private long code. Higher protection is obtained by encrypting certain sensitive message fields. This protects items such as subscriber-entered credit card numbers, PINs, etc. 2.8 Mobile station identificationThe electronic serial number (ESN) is used to uniquely identify a mobile station to any PCS system. The ESN has 32, 40, 48 or 56 bits. The user subscription is identified by the ITU-T Recommendation E.212 International Mobile Station Identity (IMSI). The IMSI consists of up to 15 numerical characters (0-9). The first three digits of the IMSI are the mobile country code (MCC) and the remaining digits are the national mobile station identity (NMSI). The mobile station can also be assigned a temporary mobile station identity (TMSI). The TMSI is used to hide the identity of the user. It also allows for shorter addressing. The TMSI consists of a TMSI code and TMSI zone. The TMSI is assigned locally. The TMSI zone provides the identity of the network element which assigned the TMSI code.
FIGURE 8/1073...[D08] = 6.5 CM In addition to supporting both 8.5 kbit/s and 13.3 kbit/s speech services, the CDMA PCS system supports a range of data services. These include asynchronous data and facsimile, which are supported by TIA/EIA IS-99; in addition, packet data is supported by TIA/EIA IS-657. Point-to-point and broadcast short messaging are supported by TIA/EIA IS 637. BIBLIOGRAPHY ANSI J-STD-018. Recommended Minimum Performance Requirements for 1.8 to 2.0 GHz Code Division Multiple Access (CDMA) Personal Stations. American National Standards Institute. EIA/TIA-533. Mobile Station – Land Station Compatibility Specification. Electronic Industries Association/Telecommunications Industry Association. TIA/EIA IS-96-A. Speech Service Option Standard for Wideband Spread Spectrum Digital Cellular System. Telecommunications Industry Association/Electronic Industries Association. ANNEX 6
General description of the composite CDMA/TDMA system 1 IntroductionThis Trial Use Standard J-STD-017/Interim Standard IS-661 (the Standard or document) has been produced by the Composite CDMA/TDMA/FDMA Technical Ad Hoc Group (TAG) of the Joint Technical Committee on Wireless Access (JTC). This Trial Use/Interim Standard describes the system design which was pioneered by the Omnipoint Corporation for use in the United States Personal Communications Services (PCS) frequency bands. This standard covers the system implementation and operation in the 1 850 to 1 990 MHz licensed frequency bands, within the public switched telecommunications network (PSTN). 2 Technical overviewThe composite CDMA/TDMA (CCT) system provides an architecture that is optimized for PCS, utilizing specific benefits of FDMA, TDMA, and CDMA technologies to provide multiple user access to the PCS network. The system employs direct sequence spread spectrum (DSSS) with TDMA, FDMA, and CDMA for PCS digital communications RF links. The use of the combined technologies will: – help mitigate the PCS link performance degradation caused by multipath propagation conditions experienced in typical mobile PCS environments. – help mitigate problems of interference with OFS users near the PCS operating area. The technology can: – accommodate the full range of mobile handover conditions, including those at freeway speed; – permit use of a bandwidth efficient frequency reuse factor of N 3. Up to 32 simultaneous users per RF channel can be accommodated, and a variable data rate up to 256 kbit/s (full duplex) is available to any user.
Directory: dms pubrec -> itu-r -> rec rec -> Recommendation itu-r bt. 1833-2 (08/2012) rec -> Rec. Itu-r p. 681-6 rec -> Recommendation itu-r m. 585-3 Assignment and use of maritime mobile service identities rec -> Rec. Itu-r ra. 611-3 rec -> Recommendation itu-r f. 383-9 (02/2013) rec -> Recommendation itu-r m. 1801-2 (02/2013) rec -> Rec. Itu-r sm. 1132-2 rec -> Recommendation itu-r m. 1459 (05/2000) rec -> Recommendation itu-r sa. 515-4 Frequency bands and bandwidths used for satellite passive sensing rec -> Recommendation itu-r bs. 1738-1 (10/2015) Download 0.5 Mb. Share with your friends:
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